With the trend towards smart cities, the use of Unmanned Aerial Vehicles (UAVs) is becoming more and more diverse. An economical and insightful way to study the use of UAV s in cities is through the utilization of computer simulations. However, currently available simulators are only of limited use to investigate such scenarios: often they have been developed for a dedicated use case, can only handle single UAV s, or the software was not made available with an open license. In this paper, we present AirMobiSim, a modular and microscopic UAV simulation framework, which is available under a GPLv2 license. AirMobiSim provides the basis for the creation of kinematic and energy models for different UAV types. It can support an arbitrary number of UAV s and can be coupled with other simulators via open interfaces, for example to examine systems using wireless communication between UAVs. We furthermore present our approach for model-building and show that AirMobiSim can already accurately reproduce existing work. We also highlight current limitations and show prospects for future work.